This invention broadly relates to urea-formaldehyde polymers. More particularly, this invention relates to thermoset cross-linked urea-formaldehyde polymer matrix compositions and precursors and molding or casting compositions thereof.
Urea-formaldehyde resins are manufactured on a large scale and used in molding compositions, foams for cavity wall insulation, adhesives such as those used in the preparation of plywood, etc. Other amino polymers, somewhat similar to urea-formaldehyde materials, are melamine-formaldehyde polymers. One principal distinction between common urea-formaldehyde polymers and melamine-formaldehyde polymers is that the latter contains cyclic structures. Urea-formaldehyde polymers, on the other hand, are generally of a linear nature. Cyclic structures in polymer compositions have been observed to improve product hardness, strength, heat distortion and water resistance.